Project 1: The Instrument

Exercise 1.1 Exposure

The brief

The histogram is a graphical representation of exposure – the camera’s sensitivity to light. Even though the pictures look the same, the histogram data shows that in a matter of seconds the world changes, and these subtle differences are recorded by the camera.

Take three or four exposures of the same scene. Don’t change anything on the camera and keep the framing the same. Preview the shots on the LCD screen. Now bring up the histogram on the preview screen. As you page through the images you can see small variations in the histograms.

Refine the test conditions (shooting on a tripod to fix the framing, moving indoors and closing the curtains to exclude daylight). Note how the histograms change.

Add the sequence to your learning log with the time info from your camera’s shooting data as your first images for Part One.

Log

As instructed I set my camera mode to Program and auto focus. I deliberately chose subjects that contained a high contrast. Each series of 3 shots in this exercise were taken at 2 second intervals.

I shot this first sequence of 3 images outdoors hand held, although I choose a subject which would be reasonably static. The framing changes between each image are obvious and apart from the movement caused by hand holding the camera, there were changes in light and wind between exposures. Both of these factors account for the variations between the histograms even though there were no changes by the camera to the shooting settings. The range of the mean (average intensity value) was 8.05.

_MG_4067 hand held 1

Handheld Outdoor  15:16:24  ISO:400 Fstop:11  Exposure:1/250 sec

_MG_4068 hand held 2

Handheld Outdoor  15:16:26  ISO:400 Fstop:11  Exposure:1/250 sec

_MG_4069 hand held 3

Handheld Outdoor  15:16:26  ISO:400 Fstop:11  Exposure:1/250 sec

I then shot the same subject with a tripod. There were no framing changes between the exposures, however were some changes caused by the light and wind. Consequently I would expect the variation between the histograms to be less than the first series and in fact the range of the mean (average intensity value) was only 4.61.

_MG_4083 Tripod 4

Tripod Outdoor  15:27:22  ISO:400  Fstop:13  Exposure:1/250 sec

_MG_4084 Tripod 5

Tripod Outdoor  15:27:24  ISO:400  Fstop:13  Exposure:1/250 sec

_MG_4085 Tripod 6

Tripod Outdoor 15:27:26  ISO:400  Fstop:13  Exposure:1/250 sec

Following this I shot indoors using a tripod, initially I chose a subject I thought would have a high contrast. There will still have been subtle changes in light levels between the shots and I would expect the variation between the histograms to be less than the outdoor series, as although the light conditions were not controlled, they were less variable. As I thought the range of the mean (average intensity value) was now only 3.24.

_MG_4141 Tripod indoors  7

Tripod Indoor 16:13:39  ISO:400  Fstop:5  Exposure:1/60 sec

_MG_4142 Tripod indoors  8

Tripod indoor 16:13:41  ISO:400  Fstop:5   Exposure:1/60 sec

_MG_4143 Tripod indoors  6

Tripod indoors  16:13:43  ISO:400  Fstop:5   Exposure:1/60 sec

On reviewing the histogram I could see that the subject had a greater tonal range than the previous subject so shot another that would have a more similar profile to the outdoors subject. This subject gave me this and I found that the range of the mean (average intensity value) was now only 0.1.

_MG_4097 tripod 10

Tripod indoor  15:38:12  ISO:400 Fstop:4.5  Exposure:1/25 sec

_MG_4099 tripod 11

Tripod indoors  15:38:14  ISO:400  Fstop:5 Exposure:1/25 sec

_MG_4099 tripod 12

Tripod indoor  15:38:16  ISO:400 Fstop:5   Exposure:1/25 sec

Learning points:

To be aware that each exposure needs carefully reviewing when shooting a sequence as there will be variations in the exposure and quality. I can see how reviewing the histogram at the time if capture can help me to make decisions about how to adjust an element to improve the image whilst shooting, especially when shooting subjects with a high contrast.